Advances in amination catalysis

ABSTRACT

Provided herein are catalysts useful in reductive amination, which include nickel, copper, zirconium and/or chromium, oxygen, and tin. The presence of the tin increases the selectivity of the catalyst in reductive aminations over the catalysts of the prior art.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This invention claims priority to U.S. Provisional PatentApplication serial No. 60/340,658 which was filed Dec. 14, 2001 andwhich is currently still pending.

TECHNICAL FIELD

[0002] This invention relates to catalysts useful in the preparation ofamines by reductive amination. More particularly, it relates tocatalysts and processes for their use in the production of amines fromalcohols, ketones, and aldehydes. Catalysts according to the inventioncomprise new combinations of metallic components, which new combinationsin such catalysts yield improved performance in a reductive aminationprocess that employs the catalysts provided.

BACKGROUND

[0003] Strictly speaking, “reductive amination” refers to the reactionof an aldehyde or ketone with ammonia (or a primary or secondary amine)and hydrogen in the presence of a metallic hydrogenation catalyst togive a primary, secondary, or tertiary amine product. Primary andsecondary alcohols also undergo the same reaction, except that hydrogenis not consumed in the reaction. It has been found in general thatcatalysts useful in reductive amination of aldehydes and ketones arealso useful in the amination of alcohols, though the reduction of analcohol in general requires considerably higher temperature.

[0004] Catalysts useful in reductive amination and alcohol aminationprocesses have been the subject of a large volume of work by chemists,and the prior art is replete with patents concerning catalytic materialsand/or processes using catalytic materials as the including thefollowing U.S. Pat. Nos. 6,159,894; 6,057,442; 6,037,295; 6,046,359;5,986,138; 5,958,825; 5,723,641; 5,367,112; and 4,152,353, as well asPCT International Applications WO 96/01146 and WO 94/24091. All patentsand patent application publications mentioned herein are incorporated byreference thereto in their entirety.

[0005] Catalysts useful in reductive amination have often historicallycomprised metals such as Ni, Co, and Cu as the active component, and aresometimes referred to as hydrogenation/dehydrogenation catalysts becausethey are active in both types of reactions. Other elements from thePeriodic Table of the Elements are frequently incorporated into thecatalyst to optimally tailor the activity or selectivity of the catalystfor the particular process in which it is employed. U.S. Pat. Nos.4,153,581; 4,409,399; 4,152,353 are descriptive of some of the moresuccessful types of reductive amination catalysts. Habermann, in U.S.Pat. No. 4,153,581, discloses a method of preparing amines using acatalyst comprising from about 20 to about 90 percent cobalt, from about8 to about 72 percent copper, and from about 1 to about 16 percent of athird component selected from the group consisting of iron, zinc,zirconium, and mixtures thereof. The catalyst of U.S. Pat. No. 4,153,581is specified to comprise at least about 20 percent cobalt. Since cobaltis a relatively expensive metal, it is desirable for practical reasonsto have at hand a catalyst useful in the reductive amination ofalcohols, etc., which has equal or superior activity to cobalt-bearingcatalysts at a reduced cost over the cobalt-bearing catalysts.

[0006] Reductive amination process conditions are typically used to makeprimary amines by reaction of an alcohol with ammonia. Good selectivityto the primary amine is usually achievable when reacting a secondaryalcohol is the presence of excess ammonia over a suitable catalyst andunder reaction conditions known to those skilled in the art. Primaryalcohols as reactant, however, under the same conditions and catalystgive rise to lower primary amine selectivity, in favor of significantlyhigher secondary amine product and significantly higher undesirable“hydrogenolysis” by-products, especially at higher levels of alcoholconversion. The hydrogenolysis by-products are formed by reductivecleavage, or the formal addition of hydrogen across C—C, C—O, and C—Nbonds.

[0007] In the case of the amination of diethylene glycol, the primarycommercially-useful products are 2-aminoethoxyethanol, morpholine, andbis(aminoethyl) ether. By-products formed by hydrogenolysis reactionsand related aminated hydrogenolysis by-products include: methane, carbondioxide, ethylene glycol, ethanol, ethylamine, ethanolamine,ethylenediamine, 2-methoxyethanol, and 2-methoxyethylamine. Highermolecular weight by-products such as N-ethylmorpholine,N-aminoethylmorpholine, 2-(N-ethylaminoethoxy)ethanol, etc., are alsoformed under reaction conditions. The formation of these materials leadsto lower yields of the desired products, and also complicates thepurification process. A catalyst that yields less of these by-productsattendant to the production of desired molecules is advantageous from acommercial perspective.

[0008] U.S. Pat. No. 4,152,353 discloses catalysts containing Ni(20-49%), Cu (36-79%), and Fe, Zn, and/or Zr (1-15%) useful in theconversion of alcohols to primary amines. U.S. Pat. No. 6,057,442described catalysts containing Ni (14-70% as NiO), Cu (1-30% as CuO),and Zr (20-85% as ZrO₂), with Al₂O₃ and/or MnO₂ (0-10%), useful in theconversion of alcohols to amines. Examples in this patent give resultsin the amination of diethylene glycol to 2-aminoethoxyethanol andmorpholine. However, the examples in these patents do not specify theselectivities to hydrogenolysis by-products. However, in our experiencesimilar catalysts afford relatively high levels of hydrogenolysisby-products in the amination of diethylene glycol. In practice, the highlevels of these by-products present yields inferior products,purification problems, and lower overall yields of the desired amineproducts. Thus, if catalysts with improved selectivities to the desiredprimary amines over prior art reductive amination catalysts wereprovided, such catalysts would represent a significant advance in theart, commensurate with the degree of reduction of by-product formationduring their use and the cost to manufacture the catalyst.

SUMMARY OF THE INVENTION

[0009] One aspect of the present invention is a catalyst useful inreductive amination which comprises the elements nickel, copper,zirconium, tin, and oxygen. Another aspect of the invention is the useof such a catalyst in a reductive amination process.

[0010] In another aspect of the invention, there is provided a catalystuseful in reductive amination which comprises the elements nickel,copper, chromium, tin, and oxygen. Another aspect of the invention isthe use of such a catalyst in a reductive amination process.

DETAILED DESCRIPTION

[0011] We have discovered that the inclusion of tin in catalysts usefulin reductive amination results in reduction of the amounts of unwantedhydrogenolysis by-products produced during reductive amination. Use ofthe catalysts of the present invention increases the level ofselectivity to the desired amine product and minimizes by-productformation. A catalyst according to one aspect of the invention and towhich the addition of tin has shown a beneficial effect in this regardis a catalyst which contains tin, nickel, copper, chromium and oxygen. Acatalyst according to a second aspect of the invention and to which theaddition of tin has shown a beneficial effect in this regard is acatalyst which contains tin, nickel, copper, zirconium and oxygen. Thesediscoveries have led us to believe that the presence of tin in generalwhen added to a prior art catalyst useful in reductive amination thatalso contains nickel and copper will show similar beneficial effects.

[0012] Catalysts according to the invention are preferably prepared by aprocess comprising the steps of: 1) co-precipitating from an aqueoussolution containing the metal ions desired to be present in the finishedcatalyst, as their carbonate salts; 2) rinsing the co-precipitatedcarbonates to remove impurities; 3) calcining the mixture ofco-precipitated carbonates to yield a mixture of metal oxides; 4)activating the mixed metal oxides by reduction with hydrogen; and 5)formation of pellets or tablets useful for a fixed-bed process.

[0013] Catalysts according to the invention are useful in the aminationof a wide range of mono-functional and polyfunctional alcohols having awide range of molecular weights. Such alcohols include, withoutlimitation, ethylene glycol, diethylene glycol, triethylene glycol,polyethylene glycols, and polypropylene glycols. Suitable polypropyleneglycols for reductive amination with a catalyst according to theinvention include those designated as JEFFOL® PPG-230, JEFFOL® PPG-400,and JEFFOL® PPG-2000 which are available from Huntsman PetrochemicalCorporation of Austin, Tex.

The Amination Process

[0014] An amination process that uses a catalyst according to theinvention is preferably carried out in a fixed-bed reactor in thepresence of excess ammonia and hydrogen, both under pressure. In analternative form of the invention, amines other than ammonia may beemployed, such as methylamine, ethylamine, etc. Reductive aminationprocesses generally known in the art which employ a catalyst may be usedin conjunction with the catalysts of the present invention.

[0015] A process according to the invention which uses a catalystprovided in accordance with the invention is not limited to a confiningset of conditions. The feed stream may be liquid, supercritical fluid,or gaseous, and the reaction product stream taken from the reaction zonemay be liquid, supercritical fluid, or gaseous. It is not necessary thatthe feed stream and the reaction product stream be in the same physicalstate. The reactor design is also not narrowly critical. The feedthereto may be upflowing or downflowing, and design features in thereactor which optimize plug flow in the reactor may be employed.

[0016] The reactants may be fed as a stream, typically continuously, tothe fixed bed of the catalyst. The solid catalyst is usually in the formof pellets, tablets, extrudates, spheres, etc. The active catalystcomponents can either be unsupported or deposited on a support material,as is known to those skilled in the art, such as alumina, silica, etc.The reaction occurs in the bed and thus the bed defines the reactionzone. The effluent from the bed or the reaction zone is also a streamcomprising the unreacted components of the feed stream and the principalamine reaction products, plus a number of other amine compounds.

[0017] The conditions for reaction are also not narrowly limited. Forexample, the pressures for carrying out the process may range from about1.90 MPa (300 psig) to about 27.5 MPa (4000 psig), more preferably fromabout 8 MPa to about 14 MPa. In addition, the process may typically becarried out at temperatures from about 120° C. to about 300° C.,preferably from about 150° C. to about 250° C.

[0018] The following examples are intended for the purpose ofillustrating this invention and should not be construed as beingdelimitive of the scope of the invention in any way. In order to makedirect comparisons of the various catalysts evaluated, a specific set ofreaction conditions was chosen. As is well known in the art, the productmixtures of any reaction process can be changed by varying such thingsas the feed mole ratio of reactants, product recycle, hydrogenconcentration, feed space velocity, time on organics, temperature, andthe like. The selection of these operating variables is dependent on thedesired conversions, product selectivity, and desired production rate.

[0019] In the examples which follow, the catalysts were characterized byBET surface area using a Micromeritics single point flow instrument, bytotal pore volume (“TPV”) using a Quantachrome mercury porosimeterinstrument, and by tablet crush strength, using a Chatillon instrument.

[0020] In each of the diethylene glycol amination examples which follow,the 100 cc reactor was fully charged with the test catalyst. Thecatalyst bed was subjected to a 2 hr reactivation with hydrogen at 250°C. Diethylene glycol and ammonia were both continuously fed at 100 g/hrand hydrogen gas was fed at 2.1 l/hr (calibrated at 0° C. and 1 atm).Samples were taken at several temperatures after sufficient time elapsedfor the reactor to have lined out to consistent conditions and producteffluent. The “hot spot” reaction temperature was measured bythermocouple reading on the outer skin of the reactor. Reactor effluentsamples were analyzed by GC using a capillary column and components wt%'s were determined. The following abbreviations were used to denote thefollowing chemical species: EGME is ethylene glycol monomethyl ether;EDA is ethylenediamine; BAEE is bisaminoethylether; 2-aminoethoxyethanolis AEE, and DEG is diethylene glycol.

CATALYST PREPARATIONS COMPARATIVE EXAMPLE 1

[0021] Catalyst containing Ni—Cu—Zr. At room temperature with efficientmixing, a solution consisting of 2908 g (10 mol) nickel (II) nitrate *6H₂O, 358 g (1.54 mol) copper (II) nitrate *2.5 H₂O, and 279 g (0.37 mol)of 15% zirconium acetate solution and 5 liters of deionized water, wasadded over about 2 hours to a solution of 1410 g (13.3 mol) sodiumcarbonate in 5 liters of deionized water. The resulting slurry wasfiltered to remove the mother liquor and the solid was reslurried with 6liters of deionized water and refiltered. The solid carbonate saltmixture was then dried in a vacuum oven at 110-150° C. overnight andthen calcined (1° C./min ramp to 460° C.) to decompose the carbonates tothe oxides. The resulting oxide was slurried with 4 liters of deionizedwater, filtered, reslurried with another 4 liters of deionized water,and re-filtered. The washed oxide mixture was dried in a vacuum oven at110-150° C. overnight. The dry powder was then mixed with 3 wt. %graphite and slugged into ½ inch diameter pellets.

[0022] The slugged pellets were then charged to a tube furnace forreduction. The charged reactor was flushed with nitrogen and heated to250° C. Hydrogen at about 5 mol % was then introduced into the nitrogenstream. The reactor was maintained at these conditions until no waterwas observed condensing in the exiting gas stream. The hydrogen rate wasincreased and nitrogen rate decreased in increments over about 6 hoursuntil pure hydrogen was being fed through the catalyst bed. Thetemperature was then held for 2 hours at 250° C., then increased to 325°C. and held overnight. The heat to the reactor was then turned off andthe reactor cooled. The hydrogen feed was turned off and nitrogen feedwas started to flush hydrogen from the reactor. After about an hour offlushing, air was introduced at about 5% in the nitrogen stream and anexotherm was observed to pass through the bed as some partial surfaceoxidation took place. These conditions were maintained overnight. Withno apparent exotherm in the reactor, the air flow was then increased inincrements and nitrogen decreased until pure air was fed through thecatalyst bed. The catalyst was then discharged from the reactor andformed into ⅛ inch diameter by ⅛ inch length tablets using a Stokes16-stage machine. The results of elemental analysis, BET surface area,mercury porosimetry, and crush strength testing are given in Table 1.Also given are the results of DEG amination studies. Comparative Example1 Ni-Cu-Zr % Ni % Cu % ZrO₂ % SnO % Cr SA (BET) TPV (cc/g) Ave. Crush(lb) 81.6 13.4 5.0 — — 30.0 0.106 15.0 DEG Amination, Component Wt % InReactor Effluent Hot Spot Reaction Temp.(C. °) 170° 180° 190° 200° 210°EGME + EGME-Amine 0.16 0.26 0.52 0.63 0.82 EDA 0.05 0.14 0.28 0.29 0.29Morpholine 3.53 10.81 26.11 36.90 45.60 BAEE 0.34 0.93 1.53 1.81 1.83AEE 23.07 34.37 34.13 29.94 24.69 DEG 70.70 47.69 26.67 16.36 11.59Heavies 0.83 2.38 3.75 4.51 3.89 % DEG conversion 29.30 52.31 73.3383.64 88.41

EXAMPLE 2

[0023] Catalyst containing Ni—Cu—Zr—Sn. This catalyst is similar informulation to that described in Comparative Example 1, except that Snwas incorporated into the formulation using tin(IV) tetrachloride asreagent.

[0024] A metal salt solution was prepared, consisting of 2908 g (10 mol)nickel (II) nitrate *6 H₂O and 358 g (1.54 mol) copper (II) nitrate *2.5H₂O, 301 g (0.40 mol) zirconium acetate (15% solution), 126 g (0.36 mol)tin tetrachloride, and 5 liters of deionized water. This solution and abase solution, consisting of 1415 g (13.4 mol) sodium carbonate and 5liters of deionized water, were simultaneously added with efficientagitation to a reaction vessel at ambient temperature. The resultingprecipitate was filtered, washed, dried, calcined, reduced andstabilized, and tabletted as described in Example 1. Results ofelemental analysis, BET surface area, mercury porosimetry, and crushstrength are given in Table 1. Also given are the results of DEGamination studies. Example 2 Ni-Cu-Zr-Sn % Ni % Cu % ZrO₂ % SnO % Cr SA(BET) TPV (cc/g) Ave. Crush (lb) 76.8 12.6 5.1 5.6 — 42.2 0.089 13.6 DEGAmination, Component Wt % In Reactor Effluent Hot Spot Reaction Temp.(C.°) 170° 180° 190° 200° 210° EGME + EGME-Am 0.07 0.02 0.07 0.10 0.14 EDA0.08 0.11 0.24 0.31 0.29 Morpholine 3.58 5.57 22.34 50.63 68.15 BAEE0.84 2.27 5.40 4.96 2.74 AEE 25.46 36.79 35.61 16.22 2.88 DEG 67.8250.71 22.03 5.62 0.36 Heavies 0.72 2.25 7.26 8.83 8.41 % DEG conversion32.18 49.29 77.97 94.38 99.64

[0025] The catalyst of the invention embodied in Example 2 surprisinglygave significantly lower levels of the hydrogenolysis by-products EGMEand EGME-amine at equivalent conversions than did the prior art catalystof Comparative Example 1. Also surprising was the significantly higherlevels of the desirable BAEE co-product. These positive effects areclearly ascribable to the presence of tin in the formulation. TheNi—Cu—Zr—Sn catalyst of this example was also found to be quite activein DEG amination.

COMPARATIVE EXAMPLE 3

[0026] Catalyst containing Ni—Cu—Zr. This catalyst, containing about 35%ZrO₂, was prepared using a similar procedure as in Comparative Example1.

[0027] At room temperature with efficient mixing, a solution consistingof 4362 g (15 mol) nickel (II) nitrate *6 H₂O, 537 g (2.31 mol) copper(II) nitrate *2.5 H₂O, and zirconium acetate, 3386 g (15% solution, 4.5mol) in 10 liters of deionized water, was added over about 2 hours to asolution of 2805 g (26.5 mol) sodium carbonate in 9 liters of deionizedwater. The resulting slurry was filtered and the solid washed byre-slurrying twice with 10 liters of fresh deionized water, followed byfiltration. Subsequent catalyst preparation steps were identical tothose described in Example 1. The resulting pelleted catalyst wasanalyzed and the results given in table 1. Also shown are the results ofDEG amination studies. Comparative Example 3 Ni-Cu-Zr % Ni % Cu % ZrO₂ %SnO % Cr SA (BET) TPV (cc/g) Ave. Crush (lb) 55.7 9.3 35.1 — — 66.60.086 16.7 DEG Amination, Component Wt % In Reactor Effluent Hot SpotReaction Temp.(C. °) 170° 180° 190° 200° 210° EGME + EGME-Am 0.11 0.240.43 0.68 0.75 EDA 0.03 0.09 0.20 0.29 0.26 Morpholine 1.99 7.30 16.0529.92 29.43 BAEE 0.15 0.49 0.99 1.42 1.43 AEE 18.09 29.05 34.91 32.7033.15 DEG 78.70 59.56 40.46 24.04 25.33 Heavies 0.13 1.00 2.33 3.09 2.08% DEG conversion 21.30 40.44 59.54 75.96 74.67

[0028] Results of DEG amination with the Ni—Cu—Zr catalyst ofComparative Example 3 were found to be similar to that of ComparativeExample 1, both in catalyst activity and selectivity.

EXAMPLE 4

[0029] Catalyst containing Ni—Cu—Zr—Sn. This catalyst was similar incomposition to the catalyst in Comparative Example 3, except that about5% SnO was incorporated into the catalyst using small mesh SnO powder.

[0030] A metal salt solution was prepared, consisting of 1454 g (5 mol)nickel (II) nitrate *6 H₂O and 179 g (0.77 mol) copper (II) nitrate *2.5H₂O, 1129 g (1.50 mol) zirconium acetate (15% solution) and 3.5 literdeionized water. This solution was added over 2 hr to a well agitatedslurry composed of 935 g (8.8 mol) of sodium carbonate, 29 g (0.21 mol)tin II oxide, and 3 liters of deionized water. The resulting precipitatewas filtered, washed, dried, calcined, reduced and stabilized, andtabletted as described in Example 1. Results of elemental analysis, BETsurface area, mercury porosimetry, and crush strength are given inTable 1. Also given are the results of DEG the amination studies.Example 4 Ni-Cu-Zr-Sn % Ni % Cu % ZrO₂ % SnO % Cr SA (BET) TPV (cc/g)Ave. Crush (lb) 52.8 8.8 33.3 5.1 — 67.1 0.080 20.2 DEG Amination,Component Wt % In Reactor Effluent Hot Spot Reaction Temp.(C. °) 170°180° 190° 200° 210° EGME + EGME-Amine 0.00 0.13 0.07 0.12 0.18 EDA 0.010.03 0.22 0.36 0.42 Morpholine 0.06 4.13 13.73 36.77 58.50 BAEE 0.011.09 2.86 4.93 4.38 AEE 4.44 30.84 39.45 29.01 12.77 DEG 95.15 61.0335.75 13.04 2.76 Heavies 0.14 1.11 3.44 5.82 6.26 % DEG conversion 4.8538.97 64.25 86.96 97.24

[0031] Again, surprisingly, the selectivity to the hydrogenolysisby-products EGMA and EGME-Am are low as compared to that obtained withthe catalyst of Comparative Example 3. The level of the desirable BAEEco-product is also significantly higher with the Sn-containing catalystof Example 4. The improved selectivities is attributed by the presenceof the Sn.

COMPARATIVE EXAMPLE 5

[0032] The preparation of this Ni—Cu—Cr catalyst has been described inU.S. Pat. Nos. 3,037,025 (Texaco, Godfrey) and 3,151,115 (Texaco, Moss &Godfrey). The material used in this experiment was supplied by acommercial vendor using similar procedures. The results of DEG aminationstudies are given below. Example 5 Ni-Cu-Cr % Ni % Cu % ZrO₂ % SnO % CrSA (BET) TPV (cc/g) Ave. Crush (lb) 72.0 12.0 — — 2.0 25.0 0.090 25.0DEG Amination, Component Wt % In Reactor Effluent Hot Spot ReactionTemp.(C. °) 180° 190° 200° 210° 220° EGME + EGME-Am 0.13 0.21 0.37 0.701.08 EDA 0.01 0.20 0.06 0.13 0.19 Morpholine 1.19 3.22 9.51 23.52 42.67BAEE 0.13 0.38 0.81 1.32 1.50 AEE 14.57 23.26 32.44 33.07 22.43 DEG83.41 71.47 52.76 31.14 15.15 Heavies 0.04 0.18 1.29 3.72 5.83 % DEGconversion 16.59 28.53 47.24 68.86 84.85

[0033] The results of the DEG amination study using the Ni—Cu—Crcatalyst of Comparative Example 5 show the relatively high levels of theundesirable EGME and EGME-Amine hydrogenolysis by-products.

COMPARATIVE EXAMPLE 6

[0034] Catalyst containing Ni—Cu—Cr. At room temperature with efficientmixing, a solution consisting of 2326 g (8 mol) nickel (II) nitrate *6H₂O, 462 g (1.23 mol) copper (II) nitrate *2.5 H₂O, and 194 g (0.48 mol)chromium nitrate *9 H₂O in 5.0 liters of deionized water, was added overabout 2 hours to a solution of 1161 g (11.0 mol) sodium carbonate in 5.0liters of deionized water. The resulting precipitate was filtered,washed, dried, calcined, reduced and stabilized, and tablettedessentially as described in Example 1. Results of elemental analysis,BET surface area, mercury porosimetry, and crush strength are given inTable 1. Also given are the results of DEG amination studies.Comparative Example 6 Ni-Cu-Cr % Ni % Cu % ZrO₂ % SnO % Cr SA (BET) TPV(cc/g) Ave. Crush (lb) 81.6 13.4 — — 5.0 10.1 0.106 11.0 DEG Amination,Component Wt % In Reactor Effluent Hot Spot Reaction Temp.(C. °) 190°200° 210° 220° 230° EGME + EGME-Am 0.04 0.07 0.19 0.31 0.74 EDA 0.000.01 0.03 0.07 0.11 Morpholine 0.52 1.49 5.63 14.15 39.75 BAEE 0.17 0.491.06 1.70 1.90 AEE 13.61 21.79 32.14 38.48 27.71 DEG 85.36 75.49 59.0640.36 16.60 Heavies 0.00 0.00 0.18 1.14 3.42 % DEG conversion 14.6424.51 40.94 59.64 83.40

[0035] The results of the DEG amination study using the Ni—Cu—Crcatalyst of Comparative Example 6 show the relatively high levels of theundesirable EGME and EGME-Amine hydrogenolysis by-products. The activityof this catalyst was also found to be low.

EXAMPLE 7

[0036] Catalyst containing Ni—Cu—Cr—Sn. This catalyst was formulated tobe similar to that in Comparative Example 6, except that Sn wasincorporated into the catalyst using tin (IV) chloride reagent.

[0037] A metal salt solution was prepared, consisting of 2326 g (8 mol)nickel (II) nitrate *6 H₂O and 462 g (1.23 mol) of a commercial 50%copper (II) nitrate solution, 206 g (0.52 mol) chromium nitrate *9 H₂O,92 g (0.26 mol) tin (IV) chloride *5 H₂O and 5 liters of deionizedwater. This solution and a base solution, consisting of 1166 g (11.0mol) sodium carbonate in 5 liters of deionized water, weresimultaneously added to a well agitated precipitation vessel at roomtemperature. The addition rates were adjusted to keep the pH between 7and 10, the addition taking place over about 2 hours. The resultingslurry was filtered and the metal carbonate precipitate mixturere-slurried with 6 liters of fresh deionized water and then re-filtered.The solid carbonate salt mixture was then dried in a vacuum oven at110-150° C. overnight and then calcined (1° C./min ramp to 460° C.) todecompose the carbonates to the oxides. The resulting oxide was slurriedwith 4 liters of deionized water, filtered, re-slurried with another 4liters of deionized water, and re-filtered. The washed oxide mixture wasdried in a vacuum oven at 110-150° C. overnight. The dry powder was thenmixed with 3 wt. % graphite and slugged into ½ inch diameter pellets.

[0038] The slugged pellets were then charged to a tube furnace forreduction and stabilization using a similar procedure to that outlinedin Comparative Example 1. The catalyst slugs were then discharged fromthe reactor, ground to powder, and formed into ⅛ inch diameter by ⅛ inchlength tablets using a Stokes 16-stage machine. The results of elementalanalysis, BET surface area, mercury porosimetry, and crush strength aregiven in Table 1. Also given are the results of the DEG aminationstudies. Example 7 Ni-Cu-Cr-Sn % Ni % Cu % ZrO₂ % SnO % Cr SA (BET) TPV(cc/g) Ave. Crush (lb) 77.2 12.6 — 5.1 5.0 28.3 0.130 5.3 DEG Amination,Component Wt % In Reactor Effluent Hot Spot Reaction Temp.(C. °) 180°190° 200° 210° 220° EGME + EGME-Am 0.03 0.06 0.12 0.22 0.31 EDA 0.020.08 0.15 0.19 0.17 Morpholine 2.00 8.06 22.32 46.83 63.57 BAEE 0.622.02 4.03 4.69 3.33 AEE 21.78 33.30 34.00 19.96 6.68 DEG 74.42 51.8027.42 8.31 1.35 Heavies 0.27 1.94 5.22 7.53 8.40 % DEG conversion 25.5848.20 72.58 91.69 98.65

[0039] The catalyst of Example 7 was found to give significantly lowerEGME and EGME-Amine hydrogenolysis by-products, and significantly higherof the desirable BAEE co-product over the catalyst of ComparativeExamples 5 and 6. Again, increased selectivity is attributable to thepresence of Sn.

[0040] Examples 8 and 9 below show amination results of polypropyleneglycols JEFFOL® PPG-230 and JEFFOL® PPG-2000 respectively, using theNi—Cu—Zr—Sn catalyst of this invention prepared in accordance withExample 2. The reactor employed for Examples 8 and 9 is a 100 cc tubularreactor, using 100 g/hr of DEG, 100 g/hr of ammonia, 0.5 mol/hr H₂ andoperated at 2000 psi. Samples were taken after conditions stabilized for2 hours, then stripped of water and lights, and titrated to determinethe extent of the amination achieved. Example 8 Ni-Cu-Zr-Sn % Ni % Cu %ZrO₂ % SnO % Cr SA (BET) TPV (cc/g) Ave. Crush (lb) 76.8 12.6 5.1 5.6 —42.2 0.089 13.6 JEFFOL  ® PPG-230 Amination Hot Spot Reaction Temp.(C.°) 180° 190° 200° 210° Total acetylatables, meq/g 8.70 8.71 8.80   8.68.Total Amine, meq/g 6.71 7.90 8.41  8.47 Primary Amine, meq/g 6.70 7.898.40  8.42 % conversion 77.1 90.7 95.7 97.5  % Primary Amine 99.9 99.999.8 99.4 

[0041] Example 9 Ni-Cu-Zr-Sn % Ni % Cu % ZrO₂ % SnO % Cr SA (BET) TPV(cc/g) Ave. Crush (lb) 76.8 12.6 5.1 5.6 — 42.2 0.089 13.6 JEFFOL  ®PPG-2000 Amination Hot Spot Reaction Temp.(C. °) 180° 190° 200° 210°Total acetylatables, meq/g 1.009 1.015 1.001 1.009 Total Amine, meq/g0.738 0.891 0.955 0.975 Primary Amine, meq/g 0.734 0.889 0.953 0.973 %conversion 73.1 87.8 95.4 96.6 % Primary Amine 99.5 99.7 99.8 99.8

[0042] The polyols of Examples 8 and 9 contain secondary alcohol groups.In these examples, the primary amine selectivities were >99%, even atthe high conversions of >95%. This is in contrast to the DEG aminationExamples 1 through 7, which show the high production of secondaryamines, which include morpholine and heavies.

[0043] The results of Examples 8 and 9 demonstrate the high activity andprimary amine selectivity of the Sn-containing catalyst of thisinvention in polypropylene glycol aminations.

[0044] Although the catalytic compositions of the present invention havebeen described as being non-supported catalysts, the present inventionalso contemplates deposition of the metallic components of the catalystcompositions onto support materials known to those skilled in the art,using techniques which are well-known in the art, including withoutlimitation, known forms of alumina, silica, charcoal, carbon, graphite,clays, mordenites, and molecular sieves, to provide supported catalystsas well.

[0045] Various aldehydes, ketones, and alcohols may be used as astarting raw material for a reductive amination process according to theinvention, as the use of such starting materials is well-known in theart of reductive amination. In the case of alcohols, the alcohols usefulas raw materials in a process according to the invention may be anyprimary, secondary, or tertiary alcohol. The alcohols known as JEFFOL®PPG-230, JEFFOL® D-230, JEFFOL® PPG-400, JEFFOL®D-2000 available fromHuntsman Petrochemical Corporation of Austin, Tex. aminate well usingthe catalysts of the invention.

[0046] Various amines, including ammonia itself, may be used as astarting raw material for a reductive amination process according to theinvention, as the use of such starting materials is well-known to thoseskilled in the art of reductive amination. Particularly useful are theorganic amines, which term includes all primary and secondary aminesknown to be useful in reductive amination processes by those skilled inthe art, and include without limitation, alkylamines, arylamines,alkylaryl amines, and polyalkylenepolyamines.

[0047] Consideration must be given to the fact that although thisinvention has been described and disclosed in relation to certainpreferred embodiments, obvious equivalent modifications and alterationsthereof will become apparent to one of ordinary skill in this art uponreading and understanding this specification and the claims appendedhereto. Accordingly, the presently disclosed invention is intended tocover all such modifications and alterations, and is limited only by thescope of the claims which follow.

What is claimed is: 1) In a catalyst useful in a reductive aminationprocess for producing amines from alcohols, aldehydes, or ketones,wherein said catalyst contains nickel, copper and chromium, theimprovement comprising the further inclusion of tin in said catalyst. 2)A catalyst according to claim 1 wherein the amount of tin in saidcatalyst is any amount between 0.20% and 20.00% by weight based upon thetotal weight of said catalyst, including every hundredth percentagetherebetween. 3) A catalyst according to claim 1 wherein the amount oftin in said catalyst is any amount between 1.00% and 7.00% by weightbased upon the total weight of said catalyst, including every hundredthpercentage therebetween. 4) A catalyst useful in reductive aminationcomprising: a) nickel, present in any amount between 40.0 and 90.0% byweight based upon the total catalyst weight; b) copper, present in anyamount between 4.0 and 40.0% by weight based upon the total catalystweight; c) tin, present in any amount between 0.20 and 20.0% by weightbased upon the total catalyst weight; d) chromium, present in any amountbetween 1.0 to 30.0% by weight based upon the total catalyst weight; ande) oxygen, present in any amount between 3.0 and 25.0% by weight basedupon the total catalyst weight. 5) A catalyst useful in reductiveamination comprising: a) nickel, present in any amount between 60.0 and80.0% by weight based upon the total catalyst weight; b) copper, presentin any amount between 6.0 and 14.0% by weight based upon the totalcatalyst weight; c) tin, present in any amount between 1.0 and 7.0% byweight based upon the total catalyst weight; d) chromium, present in anyamount between 1.0 and 5.0% by weight based upon the total catalystweight; and e) oxygen, present in any amount between 5.0 and 10.0% byweight wherein all percentages are based upon the total weight of thefinished catalyst. 6) In a catalyst useful in a reductive aminationprocess for producing amines from alcohols, aldehydes, or ketones,wherein said catalyst contains nickel, copper and zirconium, theimprovement comprising the further inclusion of tin in said catalyst. 7)A catalyst according to claim 6 wherein the amount of tin in saidcatalyst is any amount between 0.20% and 20.00% by weight based upon thetotal weight of said catalyst, including every hundredth percentagetherebetween 8) A catalyst according to claim 7 wherein the amount oftin in said catalyst is any amount between 1.00% and 7.00% by weightbased upon the total weight of said catalyst, including every hundredthpercentage therebetween. 9) A catalyst useful in reductive aminationcomprising: a) nickel, present in any amount between 40.0 and 90.0% byweight based upon the total catalyst weight; b) copper, present in anyamount between 4.0 and 40.0% by weight based upon the total catalystweight; c) tin, present in any amount between 0.20 and 20.0% by weightbased upon the total catalyst weight; d) zirconium, present in anyamount between 1.0 and 50.0% by weight based upon the total catalystweight; and e) oxygen, present in any amount between 3.0 and 25.0% byweight based upon the total catalyst weight. 10) A catalyst useful inreductive amination comprising: a) nickel, present in any amount between60.0 and 80.0% by weight based upon the total catalyst weight; b)copper, present in any amount between 6.0 and 14.0% by weight based uponthe total catalyst weight; c) tin, present in any amount between 1.0 and7.0% by weight based upon the total catalyst weight; d) zirconium,present in any amount between 3.0 and 25.0% by weight based upon thetotal catalyst weight; and e) oxygen, present in any amount between 5.0and 10.0% by weight wherein all percentages are based upon the totalweight of the finished catalyst. 11) In a catalyst useful in a reductiveamination process for producing amines from alcohols, aldehydes, orketones, wherein said catalyst contains nickel and copper, theimprovement comprising the further inclusion of tin in said catalyst.12) A catalyst according to claim 11 wherein the amount of tin presentin said catalyst is any amount between 0.20% and 20.00% by weight basedupon the total weight of said catalyst. 13) A process for producing anamine by a reductive amination process comprising the steps of: a)providing a raw material selected from the group consisting of:aldehydes, ketones or alcohols; b) contacting said raw material with anamino compound selected from the group consisting of: ammonia or organicamines under a pressure that is greater than atmospheric pressure toform a pressurized amination mixture; c) contacting said aminationmixture with a catalyst according to claim
 1. 14) A process according toclaim 13 wherein said amination mixture further comprises hydrogen. 15)A process for producing an amine by a reductive amination processcomprising the steps of: a) providing a raw material selected from thegroup consisting of: aldehydes, ketones or alcohols; b) contacting saidraw material with an amino compound selected from the group consistingof: ammonia or organic amines under a pressure that is greater thanatmospheric pressure to form a pressurized amination mixture; c)contacting said amination mixture with a catalyst according to claim 6.16) A process according to claim 15 wherein said amination mixturefurther comprises hydrogen. 17) A process for producing an amine by areductive amination process comprising the steps of: a) providing a rawmaterial selected from the group consisting of: aldehydes, ketones oralcohols; b) contacting said raw material with an amino compoundselected from the group consisting of: ammonia or organic amines under apressure that is greater than atmospheric pressure to form a pressurizedamination mixture; c) contacting said amination mixture with a catalystaccording to claim
 12. 18) A process according to claim 17 wherein saidamination mixture further comprises hydrogen.